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The Commodore 64: For the Masses Not the Classes
Dr Kenny McAlpine discusses the origins of Commodore Business Machines and its iconic home computer, the C64.
The company that would become Commodore Business Machines was founded in 1954 as a typewriter service and repair company by Jack Tramiel, a Polish immigrant who had arrived in the USA in 1947. Following a brush with insolvency when a number of Japanese firms entered the typewriter market in the early 1960s, Tramiel moved Commodore into mechanical adding machines and then to digital calculators when the Japanese moved into the adding machines market a few years later. Calculators suited Commodore well, until Texas Instruments, who supplied Commodore with components, began producing calculators themselves at a retail price point that was lower than it cost Commodore for the parts to build one.
The ensuing calculator war saw Commodore lose $5 million, forcing an emergency $3 million investment by the Canadian financier Irving Gould. Gould’s cash injection saved Commodore and financed its purchase of MOS Technology, a semiconductor design and fabrication company based in Pennsylvania. Tramiel had seen how effectively Texas Instruments had been able to integrate their business upwards, growing their calculator operation from their existing expertise in chip manufacturing, and Tramiel was determined that Commodore would never again be exposed to that sort of risk. He strengthened Commodore’s position by integrating vertically downwards, taking the company’s expertise in system design and expanding it into integrated circuits.
In 1976, two young engineers, Steve Jobs and Steve Wozniak, approached Tramiel to demo their new home computer, the Apple II. The pair hoped that Commodore would buy the design and manufacture it. Tramiel declined. He thought the deal was too expensive. But he could see the shape of things to come and committed to developing a computer system of his own. Commodore announced the PET 2001 at the Consumer Electronics Show in January 1977, claiming that it would be ready in time for the trade show in June that same year. That left just six months to design and build the prototype around the MOS 6502 processor.
The PET was a hit, but the engineers at MOS had little time to bask in the glory. Almost immediately, they started work on a series of display chips, one of which, the Video Interface Chip or VIC, was primarily designed for use in arcade video games. But following the 1977 video games crash, the result of a market flooded with dedicated one-play Pong-style home video game consoles, it proved impossible to find buyers for the new VIC chip. Tramiel, though, was more convinced than ever that there was a market for a low-cost home computer and instructed his engineers to design one for the winter 1980 Consumer Electronics Show in Las Vegas.
A young engineer called Bob Yannes showed Tramiel a working prototype that he’d been working on. His new machine, the VIC-20, had just 5 kilobytes of RAM, and 1.5 kilobytes of that was reserved for the system, leaving just 3.5 kilobytes of free user-addressable memory, barely enough to load a machine code compiler. By January 1981, with the VIC-20 selling strongly, the engineers at MOS Technology were clamouring for a new project. They decided to go ahead and produce state-of-the-art video and sound chips for the world’s next great video game machine. The team looked around at the most sophisticated hardware on the market and extrapolated from there to define all that the new chips should be able to achieve.
Thanks to Tramiel’s philosophy of vertical integration, the design team had the luxury of a microchip fabrication facility on-site, which meant that the component circuits could be tested and manufactured and run quickly and cheaply, allowing for rapid prototyping and debugging. Both the VIC 2 graphics chip and a new sound chip, the SID, designed by Bob Yannes, were completed in November 1981. At a meeting with the engineering team later that month, Jack Tramiel decided that the chips would go into a 64-kilobyte home computer. The designs for the new machine were laid out in just two days. The computer would use the same case as the VIC 20 and the same size circuit board to speed development and keep costs low.
Five working prototypes were completed just before the new year, and the new Commodore 64 debuted at the Computer Electronics Show in Las Vegas in January 1982. Inside the machine, the 64’s sound chip was orders of magnitude more advanced than anything else on the market, never mind the rudimentary bleeping of the Spectrum. The SID chip had proper ADSR amplitude envelopes and programmable filters that could be applied to multiple waveforms, while an analogue input pin on the SID allowed external signals to be routed through its filter and mixed with the onboard sound channels. The Commodore 64 felt like a hardware synth that just happened to come with a home computer built around it.
It was, without a doubt, the most powerful out-of-the-box music machine of its generation. But while the Spectrum BEEP command made it easy for the novice to code simple melodies and sound effects, Commodore’s BASIC set the bar for entry very much higher. Getting the C64 to make any kind of sound at all involved POKEing numbers directly into the SID’s memory registers, concepts that are more common to low-level assembly language programming than to basic. It would take a fairly dedicated casual user to persevere. Each of the SID’s three channels offered a bewildering array of options, all controlled by accessing specific memory registers.
Alongside the raw waveforms, triangles, sawtooth, pulse, and noise, the SID offered a range of modulation options and sources from subtle shimmery pulse-width effects through to full-on ring modulation. Even once you managed to get your head around the capabilities of the SID and the complexities of programming it, the Commodore still made things difficult. And nowhere was that more evident than with its filter. The filter on the SID is analogue, but it’s controlled digitally, and the quality of the components used in its manufacture varied considerably across the lifespan of the chip. Different batches of SID chips ended up sounding very different, and to compound matters, the equations describing the operation of the filters in the technical documentation were just plain wrong.
And so most early developers either ignored them completely or incorporated features by trial and error. Not so Commodore’s Japanese developers. Instead, they worked to those incorrect technical specifications. Rather than correct the obvious errors in their code, they produced games with out of tune sounds and filter settings that produced only quiet muffled sound at the output. As far as they were concerned, it didn’t matter that their code sounded all wrong. They had written their code correctly according to the spec, and that was all that mattered.
Commodore issued a technical note quite early on in the C64’s life to say that because of these variations, it was not advisable to include filter settings in commercial software, since it might result in unintentional sounds or even sounds which couldn’t be heard on some machines. And so filtering on the C64 became a process of trial and error. A later revision of the SID, the 8580, was designed and manufactured to the original technical specification, with linear control over the cutoff frequency and, thanks to better separation between the analogue and digital circuits, better noise and distortion characteristics.
Many gamers and most musicians, however, prefer the original 6581 chip precisely because the quirks of his filter and the grit imparted by the noise and the distortion. That quirky filtered sound, with all of its glitches was an important and characterful part of the Commodore’s voice.
What I’d like you to do now is consider the impact of the SID on video game development, and particularly video game music development. The complexity of the C64 sound hardware, coupled with an awkward implementation of the BASIC programming language, made it very difficult for users to play with the sound on the machine. And the technical element was just one aspect of the chip. To really get the most out of it, you had to code it with a high degree of musicality. As a result, it was on the Commodore 64 that the role of video composer became more specialised and more professionalised. Was this a positive or negative development?
Please post your thoughts on the discussion board, and I’ll join you again shortly for the next activity.
Commodore’s C64 was a musical powerhouse. Its Sound Interface Device – the famous SID chip – gave it the functions of a three-channel digital synthesiser.
In this video, we’ll look the development of the Commodore 64, and how its feature set came about because of cheap calculator chips and the video game crash.
Once you’ve completed the video step, I’d like you to consider the impact of the SID on video game development, and particularly video game music development.
The complexity of the C64 sound hardware, coupled with an awkward implementation of the BASIC programming language, made it very difficult for users to play with the sound on the machine. And the technical element was just one aspect of the chip. To really get the most out of it, you had to code it with a high degree of musicality. As a result, it was on the Commodore 64 that the role of video composer became more specialised and more professionalised. Was this a positive or negative development?
Please post your thoughts to the comments section below.
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Video Game Design and Development: A Bit-by-Bit History of Video Game Music: Video Game Sound and Music
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Video Game Design and Development: A Bit-by-Bit History of Video Game Music: Video Game Sound and Music
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